Piper PA-24 Comanche Service Manual page 321

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PIPER COMANCHE SERVICE MANUAL
c. Rotate the drive gear on the mapeto until the c:hamfered tooth on the distributor ,car inside the
magneto alians with the white pointer u sam throu,h the inspection hole in the magnetO housin,.
d.
WithOut allowing the feat to tum from this position, insull the mqneto with psket on the engine
ana secure with wuher! and nutS.
e. Tiabten nuts sufficiently to bold mapeto in position and yet allow it to be route(l.
f. Futen the ground lead of the timing I.iJbt to an unpainted dleW1ic portion of the ma«neto and
one posltive lead to the terminal side of the main breaker peina.
g. Turn on the timqUcht switch.
h. Route the mapcto housin, in the direction of the maplet rotation a few dqrccs until the timiftl
light comes on. Then slowly
Nm
the maplecc in oppositc direction until the timinlliJht just goes out.
Secure the mapcto housing in this position.
NOTE
Some timing lights operatc the OPPosite of the one mcntioned.
i.
Route the cnnkshaft opposite
DOnna!
roution until it is approximately 3' degrees BTC on
compresslon scroke
:-.10.
one cylinder.
NOTE
The c:rwshait should not be routed more than 10 dqrccs in direction
opposite normal roeation from thc 25 dqrce
aTe
as the pawl on the
impulse coupling (·21 m*lftetos) will enpp with the stOp pin and late
timint will be indicated throUJh the impulse coupq mcch&n.ism. If this
should happen. route c:rankshaft in
1lOrm&i
direction until sharp click is
heard. this will indicate that the impulse coupliq bu pused through
firinl position. Tum crankshaft in direction oppositc normal roution to
approximately 35 degrees BTC and proceed with
timiDI
check.
j. Turn the cn.nkshait very slowly in direction of
1l0rmal
rotation unQl the timing mark on the front
face of the ring gear a.1igns with the drilled hole in the starter or the timing
mark on the back of the
ring
,eu aligns with the crankcase pU'tinJ surfaca. At this point the liIht sbould
' 0
eue,
k. If the light does not go eue at this point. alien
timing
marks and route magneto on mountiftl
flange in the desired dirtttion and repeat the proceduR until the light goes OUt at 2S degrees before top
dead center.
CAUTION
When timing retard breaker magnetos to the engine. only main breaker
pOints arc timed. :-.lever attcrnpt to time retard breaker points to the
engine.
POWER PLANT
ISSUED: 8/18172
2
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